Knitted pile fabrics made on circular knitting machines have become well known, and efforts have previously been made to produce synthetic fur pieces comprised of fabric knitted on a circular knitting machine. So long as the product synthetic fur piece so knitted has a uniform texture, it was possible by prior art technology to produce simulated fur products which have reasonable aesthetic appearance, excellent wear properties, and commercial practicality.
However, when it is desired to closely simulate in a deep pile fabric made on a circular knitting machine a synthetic fur piece comprised of seemingly seamed together animal pelts wherein the individual pelts are longitudinally aligned relative to one another, have individually discernible, predetermined Gratzens, and have non-uniform textures (including fur fiber length variations), severe manufacturing problems arise which heretofore had no practical solutions. For one thing, to make such a synthetic fur piece, it is necessary to have the pile fiber blend vary systematically (as respects not only color, but also fiber type and local content) by a predetermined program extending from fabric wale to wale during the knitting operation in order to simulate the actual variations which occur in pelt characteristics. For another thing, it is necessary to use fabric blends which can be subsequently processed preferably in a continuous or semi-continuous manner following the actual knitting operation so as to produce a product processed fabric resembling such a desired synthetic fur piece whose exterior surface portions (or pile) varies in local density and is comprised of fibers of variable color, length and thickness, thereby to simulate an actual predetermined animal fur.
Modern circular knitting machines are designed to provide the capability of knitting complex pile patterns through the use of electromechanical and mechanical systems which can be computer controlled so that systematic pile pattern variations from wale to wale, suitable for the use in manufacturing synthetic fur pieces, can be achieved. However, such a knitting manufacturing capability does not begin to solve the problem of manufacturing fabrics resembling such a synthetic fur piece because of the necessity to perform subsequent processing thereupon.
Thus, in the deep pile knitted fabric art, for practical purposes, it is generally considered necessary to coat or impregnate the back of a knit product with some sort of coating composition which, typically with subsequent heating, tends to render the product fabric dimensionally stable, and also to give it durability by bonding the individual tufts of pile fiber into the substrate backing so that the product does not shed very easily, and so that the individual pile fibers are not easily plucked out of the stitches of the fabric backing.
In the case of synthetic fur fabrics with non-uniform transverse characteristics, it is desirable to employ a knitted deep pile fiber blend which utilizes, as a portion thereof, heat shrinkable fibers which heat shrink longitudinally within specified temperature ranges. Through the use of such heat shrinkable fibers, combined with suitable processing, it becomes possible to produce a product synthetic fur piece wherein the individual fibers of the pile have differential lengths, such as is characteristic of virtually all animal pelts. A problem arises in dimensionally stabilizing a freshly knit pile fabric through back coating because coating compositions commonly require subsequent application of elevated temperatures which are in the range of the temperatures employed for accomplishing heat shrinking of heat shrinkable fibers. Obviously, if the heat shrinkable fibers in a deep pile fabric are heat shrunk at an undesirable point in the manufacture of a synthetic fur piece, it is not possible to complete a sequence of post-knitting processing steps needed to complete the manufacture of a pelted fabric.
In addition, in the manufacture of knitted fabrics resembling natural fur pelts, it is desirable to contour shear the surface of the deep pile thereof so that its surface contour has the appearance of sewn together animal pelts of variable fur depth, as is typical of whatever type of animal fur one is trying to mimic in a given product fabric.
It was previously possible to accomplish uniform shearing of knitted fabrics in a continuous manner by passing of pre-formed deep pile knitted fabric beneath a rotating cylindrical member whose circumferential face has portions thereof so contoured that a desirable shearing is accomplished in such a pre-formed fabric. Rotating blades are located along the circumferential surfaces of the rotating cylindrical member, and, when it rotates, it cuts against a stationary knife very much in the manner of operation of a conventional type reel lawn mower. Typically, in the deep pile fabric manufacturing art, the actual knives associated with the rotating cylindrical member are put in at an angle so that, instead of just shearing, they also cut. To accomplish this action, the cross section through the knives typically presents an angle of knife cutting relative to the stationary blade, or so-called ledger blade, whereas, on a reel type lawn mower, the knives are typically almost sectioned so that individual blades pass substantially through the center of the arbour. At any rate, the rotating arbour has, in the cylindrical member employed for deep pile fabric processing, a plurality of cutting edges on it which rotate past, and in close proximity to, and even in some applications actually contact, a fixed ledger blade.
In such uniform shearing, the distance of the rest from the ledger blade was, until recently, held constant, and determined the length of the pile, which was thus always uniform. A recent invention provides a contoured rest of cylindrical shearing apparatus so that different predetermined portions of the pile of a fabric are spaced farther from the arbour and the ledger blade by the use of such a contoured rest during a shearing operation, thereby making it possible to contour shear a deep pile fabric differentially in a direction extending transversely across the fabric relative to the direction of fabric movement through such contour shearing apparatus. Such a contour shearing apparatus is shown in Norman C. Alber U.S. application Ser. No. 719,017, filed Aug. 30, 1976, now U.S. Pat. No. 4,102,023, granted July 15, 1978.
During contour shearing of a patterned deep pile fabric which has been stabilized, the fabric is registered and aligned with the contour shearing apparatus so as to control location of contour shearing relative to the pattern in the fabric. In order to be continuously contour sheared, a patterned deep pile fabric of a type and quality suitable for use in making fabrics resembling natural fur pelts must be sufficiently dimensionally stable to experience processing through such a contour shearing apparatus. If a deep pile fabric being contour sheared is insufficiently dimensionally stable, a regular pattern repeat is not achieved where it is desired in relation to the contour shearing. An Abler contour shear rest is a passive element, in effect, so that a fabric moves over it, in a continuous shearing operation, and conforms to the contour of the rest. Thus, one must first not only dimensionally stabilize and lock the pile into the backing of a given deep pile sliver knit fabric to be contour sheared, but also achieve such a dimensional stabilization without causing the heat shrinkable fiber of the pile to shrink.
So far as is known, no one has heretofore succeeded in producing a sliver knit pile fabric product comprising of seemingly seamed together animal pelts which fabric product has undergone contour shearing in good register prior to heat shrinking of pile fibers contained therein.